Virgin Galactic's spaceplane hits new heights in second powered flight

Virgin Galactic has shown the first firing of its spaceplane's chemical rocket engine was no fluke, following last month's effort with another successful outing in California. The latest test flight took the tourist-carrying space vehicle a little closer to space, literally and figuratively, with engineers now poring over data with an eye to the next round of testing.

Where some private space companies, such as Blue Origin, imagine firing tourists into space with conventional launch vehicles that blast off from the ground, Virgin Galactic's SpaceShipTwo VSS Unity works a little differently.

During the test flight last month, it was carried into the air by a mothership called WhiteKnightTwo and released at an altitude of 46,500 ft (14,173 m). Seconds later, its hybrid rocket engine was fired up for around 30 seconds to propel the plane to roughly Mach 1.9 (2,328 kph/1,446 mph) and an altitude of 84,271 ft (25,686 m).

Today's second test flight played out pretty similarly, but was set up to observe the behavior of the plane in a setup that will more closely resemble its final commercial configuration. That means its center of gravity was moved backward as passenger seats and accompanying gear were added to the cabin.

The plane also traveled higher this time, reaching an altitude 114,500 ft (35 km). According to the US Air Force standards, space begins at 264,000 ft (80.5 km), but the Kármán line, at an altitude of 330,000 ft (100 km), is the most commonly used boundary representing the start of space. It's not clear which metric Virgin Galactic prefers, but it ultimately plans to carry paying passengers to suborbital altitudes in the future.

"Today we saw VSS Unity in her natural environment, flying fast under rocket power and with a nose pointing firmly towards the black sky of space," said founder Richard Branson, who was on hand at the company's Mojave base to witness the test flights. "The pathway that Unity is forging is one that many thousands of us will take over time, and will help share a perspective that is crucial to solving some of humanity's toughest challenges on planet Earth."

After reaching supersonic speeds, the engines were shut down and the plane's re-entry feathering system was engaged. This mechanism is a point of sensitivity for Virgin Galactic, as the premature deployment of its tail booms led to a fatal test flight in 2014.

The company has since incorporated new safety devices into the tail booms and they worked as desired today (as they did last month), deploying at 60-degree angles and slowing the plane on its way down. It then glided safely to the tarmac and made a conventional, flawless landing.

Virgin Galactic's engineers are now reviewing the flight data and planning the next outing for the high-flying spaceplane. This is expected to be the final phase of testing for the SpaceShipTwo VSS Unity before it enters service. The company hasn't offered an exact timeline for when it will be complete, but Branson indicated to CNBC afterwards that it mightn't be long.

"It will be something like two or three more flights before we're actually in space," he told the network, also mentioning that once they have a safe craft that can go above 264,000 ft, he will go up himself and then soon after, astronauts will follow.